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8. Computer-controlled machining

This week I worked on building something big on a wood CNC, I need a desk for my house so that’s what I will be building.

Design

wood furniture always fascinates me, I follow a few youtube woodworkers on youtube to see how furniture are built.

I took my inspiration design from Chris Salomone desk project, mainly focusing on the desk feet and its side-veiw.

Click here to see a video of the whole design prosess

Here is the design, I made sure it is fully parametric and doesn’t break down if I change its size.

Design

Here is the side view.

sideview

Here is the back of the desk.

Back

Here I’m showing the desk stretchers and how they connect to the legs, since the legs are 3 layers of plywood, I made the stretchers to have a part going inside the middle leg layer.

streachers

The part in the middle should hold the desktop, I connected the tabletop with this part with screws to have a clean top and no joints.

Top support

Here are the front legs, showcasing the middle layer which holds the stretchers.

front legs

Here are the back legs, showcasing the middle layer which holds the stretchers.

back legs

Fusion 360 live veiw

here is a link of my design

Manufacturing

Laser-cut model

I started by cutting a laser-cut model to make sure that the joints I designed work, and they do.

Here are some pictures of the model.

laser model

laser model

laser model

CNC

kerf testing

I started by testing the CNC kerf by cutting a simple snap-fit joint till git a snug but not too tight fit, tested the fit on 18mm plywood which I am planning to use for the desk.

Design value = 17.5mm, measured value = 16.7mm.

kerf

Design value = 18mm, measured value = 17.13mm.

kerf

Design value = 20mm, measured value = 19.3mm.

kerf

after these tests, I modified the material thickness parameter to 19.5 to get the fit I want.

Cnc fixture

I used screws on the sides of the board to fix it to the sacrificial one.

fixture

Cam

I used Vcarve pro software to make the toolpath, after exporting the sketchs from fusion 360, I ordered them in autoCad.

sketchs

fusion export

After setting up the 2D vector design, I went to the cnc cam software Vcarve to make the machine code. first step is to set the stock size, I used a 2400mm X 1200mm X 18mm plywood sheet.

vcarve

after that I imported the design and arranged the pieces in the sheet.

vcarve

then from the top right, pick the cutting tool needed, in my case all on my part needed to cut, no pockets, I set the tabs locations and the milling bit type.

vcarve

and finally, simulate the tool path and make sure that everything went well.

vcarve

for another CNC project check my wild card assignment where I used the CNC to create a Male mold for vacuum forming

cut and assemble

And, here are the parts after CNC machining. machining video

Assemble

I started by gluing the 3 layers of each leg together.

Assemble

After they had dried I tested the fit of the stretcher’s joints and they fit well, they need light hammering in though.

Assemble

Assemble

After I made sure that the joints are well, I started with a test assemble, first by connecting the side stretcher to the front and back legs as shown below.

Assemble

Assemble

Assemble

Assemble

After doing that for the two sides, I connected them with the front, back, and middle stretchers.

Assemble

Assemble

Assemble

Then placed the tabletop on it and here how it looks.

Assemble

Assemble

Now I made sure everything fits well, I disassembled it, sanded it for way too long to get a smooth finish especially on the legs, then spray paint it with lacquer.

Here is the desk ready for use in my new house.

final

final

final

Files

All files can be downloaded from here


Last update: June 26, 2021